Chemistry

Chemistryis the science that deals with the properties of organic and inorganic substances and their interactions with other organic and inorganic substances. In the study of matter, chemistry also investigates the movement of electrons. Because of the diversity of matter, which is mostly composed of different combinations of atoms, chemists often study how atoms of different chemical elements interact to form molecules and how molecules interact with each other.Chemical compound — A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining ... > read moreMaterials science — Materials science is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... > read moreChemical bond — A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing, as well ... > read moreMolecule — In general, a molecule is the smallest particle of a pure chemical substance that still retains its composition and chemical properties. In chemistry ... > read more

Reference: Science Daily

Nanoparticle Solar Panel Coating Helps Maintain Panel Efficiency

ScienceDaily (Aug. 13, 2012) — A University of Houston researcher has developed a nanoparticle coating for solar panels that makes it easier to keep the panels clean, which helps maintain their efficiency and reduces the maintenance and operations costs.

The patent-pending coating developed by physics professor Seamus "Shay" Curran, director of UH's Institute for NanoEnergy, has successfully undergone testing at the Dublin Institute for Technology and will undergo field trials being conducted by an engineering firm in North Carolina.Curran said the June testing in Ireland and the field trials being done at Livingston & Haven in Charlotte, N.C., represent significant steps forward in moving the coating and a related technology to the marketplace. A demonstration of the coating was conducted Aug. 10, 2012 at Livingston & Haven.The Self-Cleaning Nano Hydrophobic (SCNH107TM) layer has been licensed by C-Voltaics from UH. C-Voltaics, a start-up energy company dedicated to the generation of more practical clean energy for use in off-grid and on-grid applications, will oversee marketing of the coating and a "Storm Cell," a transportable energy generator with unique patent-pending designs and engineering aspects that was also developed by Curran at UH.Solar panels need to have a clean surface to efficiently gather light from the sun, but they are often soiled by dust, pollen, water and other particles. Curran's coating acts as a barrier protection against these pollutants.The nano-thin coating repels dust, pollen, water and other particles without hindering the solar panel's ability to absorb sunlight. The coating can maintain this ideal hydrophobic surface for years, reducing overall maintenance."A dirty solar panel can reduce its power capabilities by up to 30 percent," Curran said. "The coating essentially makes the panel self-cleaning."While the coating is designed for use on solar panels, Curran believes it could also have widespread applications as an anti-corrosive coating for other materials.UH is a shareholder in C-Voltaics, which focuses on using technology to alleviate the significant costs of solar energy service and maintenance, which are key issues in solar energy generation and storage."This is where you see the university transitioning a technology from the lab to the community and making an economic impact," Curran said.Curran developed the coating in conjunction with his work on building transportable, off-grid solar-powered generator for residential and commercial use.Curran's development of the storm cell system stems from his family's experience during Hurricane Ike in September 2008. Curran, his wife and three young sons stocked up and hunkered down as Ike approached the Texas coast. They woke up the next morning after the storm passed with the house intact, but powerless."My wife said to me, 'How long have you been working in solar energy? The sun is shining but we don't have any electricity. Why don't you build us a portable solar unit for the next time this happens?'"The dutiful husband did as he was asked.The solar-powered Storm Cell is designed to be used much in the same way as a diesel generator, except it's quiet and has no emissions. It consists of a square storage trailer with solar panels attached to retractable arms that can be manually unfurled as needed and then stored inside the trailer.The unit built by Curran and his team produces two-to-five kilowatts and charges a backup battery. That's enough power for an air-conditioning system, some light and a TV. But Livingston & Haven has built an even larger unit that could fully power a 3,000-square-foot house. Curran said there also are a number of commercial uses for the generators such as oil and gas drill sites and farms.The generator system will be engineered and sold by C-Voltaics and Livingston & Haven.Curran has been involved in solar energy research for many years and also has been working on improving the efficiency of thin-film solar cells in terms of storing solar energy. Thin-film solar cells are lightweight, durable and easy to use. Researchers are trying to improve their efficiency in terms of storage capability so that they are competitive with silicon cells.Curran also has created several innovations that relate to the next generation of solar devices used to produce electricity. These devices are all plastic, as opposed to the current devices that use silicon or metal alloys, which take up space and can be costly.Reference: Science Daily

Cellular Basis for How Anti-Aging Cosmetics Work Identified

ScienceDaily (Aug. 13, 2012) — A team of investigators from UC Davis and Peking University have discovered a mechanism that may explain how alpha hydroxyl acids (AHAs) ― the key ingredient in cosmetic chemical peels and wrinkle-reducing creams ― work to enhance skin appearance. An understanding of the underlying process may lead to better cosmetic formulations as well as have medical applications.

The findings were published in theJournal of Biological Chemistry in an article entitled "Intracellular proton-mediated activation of TRPV3 channels accounts for exfoliation effect of alpha hydroxyl acids on keratinocytes."AHAs are a group of weak acids typically derived from natural sources such as sugar cane, sour milk, apples and citrus that are well known in the cosmetics industry for their ability to enhance the appearance and texture of skin. Before this research, little was known about how AHAs actually caused skin to flake off and expose fresh, underlying skin.The cellular pathway the research team studied focuses on an ion channel ― known as transient receptor potential vanilloid 3 (TRPV3) ― located in the cell membrane of keratinocytes, the predominant cell type in the outer layer of skin. The channel is known from other studies to play an important role in normal skin physiology and temperature sensitivity.In a series of experiments that involved recording electrical currents across cultured cells exposed to AHAs, the investigators developed a model that describes how glycolic acid (the smallest and most biologically available AHA) enters into keratinocytes and generates free protons, creating acidic conditions within the cell. The low pH strongly activates the TRPV3 ion channel, opening it and allowing calcium ions to flow into the cell. Because more protons also enter through the open TRPV3 channel, the process feeds on itself. The resulting calcium ion overload in the cell leads to its death and skin exfoliation."Our experiments are the first to show that the TRPV3 ion channel is likely to be the target of the most effective skin enhancer in the cosmetics industry," said Jie Zheng, professor of physiology and membrane biology at UC Davis and one of the principal investigators of the study. "Although AHAs have been used for years, no one until now understood their likely mechanism of action."Besides being found in skin cells, TRPV3 also is found in cells in many areas of the nervous system and is sensitive to temperature as well as acidity. The authors speculate that the channel may have a variety of important physiological functions, including pain control.Lead author Xu Cao, who conducted the study with UC Davis scientists as a visiting student from Peking University Health Science Center, focuses on TRPV3 channel research. With a team of researchers in China, he recently contributed to the discovery that a mutation in TRPV3 leads to Olmsted syndrome, a rare congenital disorder characterized by severe itching and horny skin development over the palms of the hands and soles of the feet. While in the UC Davis Department of Physiology and Membrane Biology, Cao discovered that AHAs also utilize the TRPV3 channel."Calcium channels are becoming increasingly recognized as having vital functions in skin physiology," said Cao. "TRPV3 has the potential to become an important target not only for the cosmetics industry but for analgesia and treating skin disease."The other study author and co-principal investigator is KeWei Wang of Peking University School of Pharmaceutical Sciences, where the research was conducted.The research was funded with grants to KeWei Wang from the National Science Foundation of China and the Ministry of Education in China, the China Scholarship Council, and to Zheng from the National Institutes of Health.

Reference: Science Daily

1.5 Million Years of Climate History Revealed After Scientists Solve Mystery of the Deep

ScienceDaily (Aug. 9, 2012) — A new study has successfully reconstructed temperature from the deep sea to reveal how global ice volume has varied over the glacial-interglacial cycles of the past 1.5 million years.

Scientists have announced a major breakthrough in understanding Earth's climate machine by reconstructing highly accurate records of changes in ice volume and deep-ocean temperatures over the last 1.5 million years.The study, which is reported in the journal Science, offers new insights into a decades-long debate about how the shifts in Earth's orbit relative to the sun have taken Earth into and out of an ice-age climate.Being able to reconstruct ancient climate change is a critical part of understanding why the climate behaves the way it does. It also helps us to predict how the planet might respond to human-made changes, such as the injection of large quantities of carbon dioxide into the atmosphere, in the future.Unfortunately, scientists trying to construct an accurate picture of how such changes caused past climatic shifts have been thwarted by the fact that the most readily available marine geological record of ice-ages -- changes in the ratio of oxygen isotopes (Oxygen 18 to Oxygen 16) preserved in tiny calcareous deep sea fossils called foraminifera -- is compromised.This is because the isotope record shows the combined effects of both deep sea temperature changes, and changes in the amount of ice volume. Separating these has in the past proven difficult or impossible, so researchers have been unable to tell whether changes in Earth's orbit were affecting the temperature of the ocean more than the amount of ice at the Poles, or vice-versa.The new study, which was carried out by researchers in the University of Cambridge Department of Earth Sciences, appears to have resolved this problem by introducing a new set of temperature-sensitive data. This allowed them to identify changes in ocean temperatures alone, subtract that from the original isotopic data set, and then build what they describe as an unprecedented picture of climatic change over the last 1.5 million years -- a record of changes in both oceanic temperature and global ice volume.Included in this is a much fuller representation of what happened during the "Mid-Pleistocene Transition" (MPT) -- a major change in Earth's climate system which took place sometime between 1.25 million and 600 thousand years ago. Before the MPT, the alternation between glacial periods of extreme cold, and warmer interglacials, happened at intervals of approximately 41,000 years. After the MPT, the major cycles became much longer, regularly taking 100,000 years. The second pattern of climate cycles is the one we are in now. Interestingly, this change occurred with little or no orbital forcing."Previously, we didn't really know what happened during this transition, or on either side of it," Professor Harry Elderfield, who led the research team, said. "Before you separate the ice volume and temperature signals, you don't know whether you're seeing a climate record in which ice volume changed dramatically, the oceans warmed or cooled substantially, or both.""Now, for the first time, we have been able to separate these two components, which means that we stand a much better chance of understanding the mechanisms involved. One of the reasons why that is important, is because we are making changes to the factors that influence the climate now. The only way we can work out what the likely effects of that will be in detail is by finding analogues in the geological past, but that depends on having an accurate picture of the past behaviour of the climate system."Researchers have developed more than 30 different models for how these features of the climate might have changed in the past, in the course of a debate which has endured for more than 60 years since pioneering work by Nobel Laureate Harold Urey in 1946. The new study helps resolve these problems by introducing a new dataset to the picture -- the ratio of magnesium (Mg) to calcium (Ca) in foraminifera. Because it is easier for magnesium to be incorporated at higher temperatures, larger quantities of magnesium in the tiny marine fossils imply that the deep sea temperature was higher at that point in geological time.The Mg/Ca dataset was taken from the fossil record contained in cores drilled on the Chatham Rise, an area of ocean east of New Zealand. It allowed the Cambridge team to map ocean temperature change over time. Once this had been done, they were able to subtract that information from the oxygen isotopic record. "The calculation tells us the difference between what water temperature was doing and what the ice sheets were doing across a 1.5 million year period," Professor Elderfield explained.The resulting picture shows that ice volume has changed much more dramatically than ocean temperatures in response to changes in orbital geometry. Glacial periods during the 100,000-year cycles have been characterised by a very slow build-up of ice which took thousands of years, the result of ice volume responding to orbital change far more slowly than the ocean temperatures reacted. Ocean temperature change, however, reached a lower limit, probably because the freezing point of sea water put a restriction on how cold the deep ocean could get.In addition, the record shows that the transition from 41,000-year cycles to 100,000-year cycles, the characteristic changeover of the MPT, was not as gradual as previously thought. In fact, the build-up of larger ice sheets, associated with longer glacials, appears to have begun quite suddenly, around 900,000 years ago. The pattern of Earth's response to orbital forcing changed dramatically during this "900,000 year event," as the paper puts it.The research team now plan to apply their method to the study of deep-sea temperatures elsewhere to investigate how orbital changes affected the climate in different parts of the world."Any uncertainty about Earth's climate system fuels the sense that we don't really know how the climate is behaving, either in response to natural effects or those which are man-made," Professor Elderfield added. "If we can understand how earlier changes were initiated and what the impacts were, we stand a much better chance of being able to predict and prepare for changes in the future."

Reference: Science Daily

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